When you're working with young individuals is
make sure you assess maturity because it's going
to be influential and should be influential in
terms of your decision making. for maybe talent
identification if there's much of that going
on within weightlifting. I know it's generally
a smaller cohort of athletes, so we don't have
as much kind of de -selection and recruitment
going on. But we need to assess maturity to factor
that in when we're interpreting performance.
And also it's obviously going to be useful from
a developmental standpoint to actually be prioritizing
appropriate things to align natural development
with an appropriate kind of training stimulus.
All right, Dr. Stefanie Morris, it's my pleasure
to have you on Evidence Strong Show for the second
time. My pleasure having you again and we'll
be talking maturation and growing up and also
becoming a weightlifter. So if you could briefly
introduce yourself, that would be amazing. Thanks
again for the invite, Alex. Good to talk about
weightlifting and good to be at the end of the
PhD journey. So yeah, a bit about me. So recently
just finished the PhD, which the kind of overarching
topic was youth weightlifting. And yeah, main
role is lecturing in strength and conditioning.
So that's kind of how I got into weightlifting
is from the using weightlifting as a training
modality, if you like. And then alongside that,
obviously get involved in the coaching. So coaching
weightlifting with British Weightlifting. and
also coaching strength and conditioning in our
Youth Athletic Development Centre at Cardiff
Met. Okay, so we have to start with some kind
of definition of what relative age and biological
maturity are. So yeah, relative age kind of refers
to an individual's calendar age, if you like.
In relation to the cut -off age within sport,
so the cut -off age that's normally used to define
chronological age groups, what we find are what
we call relative age effects. So often in sport,
there's a bias towards what we call BQ1 athletes,
so individuals born in the birth quartile 1 or
that first quartile relative to the cut -off
age. And so that's probably most common in a
lot of sports. But likewise, there are some sports
where actually there's a bias towards BQ4 athletes
or those kind of... relatively younger individuals
compared to that cutoff age. But that's less
common. And that would be in sports such as like
gymnastics, diving. We're actually... kind of
smaller might actually be advantageous I guess
important to note that sometimes there's some
confusion between relative age and maturity but
they need to be recognized as kind of separate
constructs if you like so just because you have
a relatively older athlete doesn't mean that
they'll actually be more mature so biological
maturity refers to that progress in terms of
maturation or progressing to a fully mature state
so different to relative age which relative age
is kind of that calendar date affected by their
date of birth whereas maturity refers to kind
of the state in terms of that biological maturation.
Please tell us how did you design the study?
It kind of came about looking at common biases
in talent identification and like youth sport
in general and what we know is that in youth
sport generally individuals are grouped by chronological
age and that means that we do get these biases
so we get relative age effects and we get generally
a bias towards early maturing individuals so
particularly in boys we know that early maturers
generally are kind of stronger heavier potentially
more confident than their peers and that leads
to athletic advantages and what we knew was that
these biases were common in a lot of other sports
so there's been a lot done in football for example
age effects and maturity biases but um there
really hadn't been much done in weightlifting
there were a couple of studies that looked at
relative age effects but actually maturity is
arguably a little bit more important and definitely
more influential as well so we just wanted to
fill a bit of a gap there and explore maturity
and also look at the influence as well so we
know that as individuals mature we get big changes
in strength and power and whatnot actually there
wasn't any research that looked at the relationship
between maturity and weight lifting performance.
All right. So you decided, right, we have to
have a look at young weightlifters. So who did
you invite to the study? Yeah. So it was, I went
along to the English age groups. And that was
kind of through links with British weightlifting.
So they've been really receptive to all of it.
And it was kind of like, OK, can I come along
to one of your events? And we chose the English
age groups or kind of championships because the
idea was we wanted that high level of performance.
And so we wanted to explore, actually, was there
a bias? And were we almost like selecting or
cutting off some of those individuals that weren't
then reaching those kind of higher participation
levels? So yeah, I went along to the English
age group championships and we managed to recruit,
it was 49 young weightlifters. And that was across
all of the age group categories competing. So
under 10s, under 12s, under 15s and under 17s.
And we had a spread across those age groups.
And also it was almost a 50 -50 split between
boys and girls within that cohort as well. Awesome.
What did you measure? So what we did was, so
when we look at assessing. biological maturity
what we often or what we have are kind of three
systems that we can measure maturity across if
you like so we have sexual maturity skeletal
maturity and somatic maturity and often sexual
maturity isn't used as much in practice so to
measure sexual maturity a common method is using
tanner stages where you kind of use criteria
and look at kind of like pubic hair development
and kind of categorize them obviously quite invasive
practitioner to do it and then there are self
-reported measures but they're less reliable
so commonly Sexual maturity isn't used that often.
We've then got skeletal maturity. And often that's
seen as like the gold standard way of assessing
biological maturity. But that involves x -rays.
And so obviously quite costly, also not that
accessible. But what they've recently introduced
is ultrasound equipment. And we used a kind of
equipment called sonic bone, which uses a similar
method to the x -rays and actually uses the Tanner.
white house two method to categorize and that
gives us an estimation of skeletal maturity using
ultrasound rather than the x -rays so we don't
have the kind of exposure and that we'd get with
the x -rays and also it's a lot more accessible
and so that was actually the method that we use
so um i took along the sonic bone so it's a piece
of equipment not not big at all and took measurements
so what we do with the that equipment is we take
three measurements on different sites on the
left hand and wrist area. And what it does is
it uses those measurements. So it kind of takes
like the speed of sound and attenuation and then
gives us an estimated skeletal age based off
that. That's pretty cool. Yeah, yeah. So yeah,
it's kind of fairly new and we've only just started
using that piece of equipment over the last couple
of years. And I think it's important to note
that like that would probably be seen as like
a more rigorous approach in research to estimate.
kind of maturity but likewise and one of the
review papers that we've actually published since
kind of gives guidance on that the other method
that i discussed of using somatic measurements
to determine kind of somatic maturity so that's
obviously easily accessible to coaches by just
taking height and weight and we get you know
it's reliable enough not as kind of accurate
as the sonic bone but we kind of it's a lot more
accessible in practice yeah so yeah we also took
height and weight which we input that information
to help with the equations as well and then the
individuals reported their competition performance
and so we reported obviously their maximum across.
clean and jerk and snatch their total and then
we also then converted those into relative measures
as well just to explore the influence of maturity
across absolute but also relative measures of
weight lifting performance how do you get from
height and weight to the maturity status or or
growth status of a person yeah yeah so yeah the
sonic bone kind of uses those as part of the
equation but what what we kind of typically recommend
and how we use somatic measures to get maturity
status is um using the commonly two equations
that are most commonly used and we recommend
the camison roach method which takes standing
height and also parental height as well so we
didn't actually use that in this study but generally
there's better reliability. And it uses equations
to look at what's the individual's predicted
adult height. And then from the measurement of
their standard height and weight, we can add
in seated height as well, but it doesn't make
a massive difference. And then from that, we
can determine what's their current percentage
of predicted adult height. And then from that,
we can align those percentages to a kind of maturity
status. Do you want to say what kind of analysis
did you do? at the kind of whether there was
a bias towards maturity or whether there were
relative age effects um we ran um chi -square
analysis and that basically shows us if there
is a difference to um what we'd expect so looked
at what's kind of normal distribution so how
many would we normally expect in birth quartile
one birth quartile two three four how many would
we normally expect as early on time or late matures
um and then the chi -square analysis looks at
what we'd expect compared to what we actually
found and then the second analysis was then looking
at some regression so we actually conducted rather
than linear regression we did power regression
so quite often we do linear regression when we're
looking at predictions but actually we know that
maturity isn't a linear process so what we found
was that the power regression analysis was kind
of a better fit and provided a better relationship
between those variables. So we did a power regression
analysis looking at weightlifting performance
and then skeletal age. Awesome. Are we ready
for the results? Yeah. Go there. So yeah, what
we found in terms of birth quartile, there were
no, it wasn't different to what we'd expect.
So in this cohort, there were no relative age
effects. And that was across all of the sample,
but also within the individual age groups. And
then probably the most interesting was the maturity
bias. So what we found across the group collectively
in both boys and girls individually, there was
an over -representation of... early maturers
and also more than what we'd expect of on -time
maturers. And it was particularly the under 15
age group when we looked at those across the
individual age groups. It was the under 15 age
group that saw that over -representation of early
maturers. And then the kind of second analysis,
looking at the relationships. What we found was
that really strong relationships between skeletal
age and weightlifting performance kind of as
we'd expect. So it was in the boys, skeletal
age was able to explain it was 73 % of variance
and then in the girls, 75 % of variance. And
then we actually looked at whether there was
a difference between the relationship between
weightlifting and skeletal age in boys and girls.
And there was a difference and that difference
tended to emerge around that like. 12 to 13 years
so again just kind of add into the notion of
the importance of assessing maturity And then
also differences in males and females, and they
are typically going to emerge around that adolescent
growth spurt, kind of as we'd expect. What coaches
should take away from this study? I guess the
importance initially is when you're working with
young individuals is make sure you assess maturity
because it's going to be influential and should
be influential in terms of your decision making
for maybe talent identification. If there's much
of that going on within weightlifting, I know
it's generally a smaller cohort of athletes.
we don't have as much kind of de -selection and
recruitment going on but we need to assess maturity
to factor that in when we were interpreting performance
and also it's obviously going to be useful from
a developmental standpoint to actually be prioritizing
appropriate things to align natural development
with an appropriate kind of training stimulus.
Would you have any examples for that? Yeah so
a kind of Key example might be post peak height
velocity, particularly in boys, we might see
increases in circulating hormones, which mean
that we get large increases in strength and the
ability to kind of increase muscle mass. So adding
additional load at this point in the weightlifting
movements, as long as we've got sound technical
proficiency, we'll take advantage and we'll almost
see kind of like a synergistic adaptation at
this point, potentially around that growth spurt.
So circa peak height velocity. and often we might
see this period of like adolescent awkwardness
so we might see like breakdowns in movement snatch
in particular for example um that's maybe deemed
a little bit more technical might become a little
bit clunky it might perfect lift one day next
day the athletes all over the place so at that
stage we might want to kind of pull back on some
of the technical elements and maybe use the derivatives
or parts of the movement a little bit more commonly
than the full movements and we might want to
supplement normal training with maybe some mobility
to cater for reductions in mobility that we might
see at that phase or potentially an emphasis
on like full range of movement in some of those
strength exercises and then the other one would
be typically pre -peak height velocity so before
that growth spurt generally we see a increase
in neuroplasticity so individuals can potentially
pick up movements and learn movement patterns
quite easily and so introducing weightlifting
ideally at that stage to learn the movements
and to then kind of progress and add load once
they've got that technical proficiency and kind
of potentially adding in some other neuromuscular
training at that stage to take advantage of what's
what's naturally occurring so plyometrics at
that stage a bit more of like a combined training
approach and you think coaches should be aware
in terms of differences between how to train
boys versus girls yeah so i guess one of the
things that we might want to consider is Girls,
particularly at that post peak height velocity
stage, because of their seeing natural increases
in fat mass, more so compared to boys, their
relative strength might actually kind of stay
the same. So being mindful of that. And at that
stage, we're going to try and avoid male and
female comparisons as much as possible, but also
avoid in peer to peer comparisons, particularly
in young females as well. So some of the research
from like. psychological perspective shows that
post peak heart velocity young girls are particularly
like critical and comparing themselves to peers
so from a confidence perspective an emphasis
on like individual growth and kind of got individual
group like goal setting and progress might be
particularly important in the girls but also
in the boys arguably as well avoiding that kind
of peer comparison yeah and I guess probably
so that focuses on almost like maturity status
but also considering Maturity timing as well
would be important. So whether your individual
is an early on time or late maturer, because
that then might have implications from a training
perspective as well. So again, kind of sticking
on the psychology, what we know is that. early
maturing females might see lower levels of self
-confidence compared to the males that actually
might see higher levels of self -confidence and
so being mindful of that and again avoiding peer
comparisons kind of throughout that growth spurt
and adolescent phase and obviously weightlifting
is a sport where the comparisons are really easy
we've literally got weight lifted but I think
one of the guidance that we pulled together was
adding in maybe like handicapped scoring systems
for in -house competitions where athletes are
compared to their personal best rather than always
kind of comparing to others within those kind
of categories or genders. Okay, we have some
options. Yeah. And to not discourage or write
off the athletes who are maturing later. That's
important. Yeah, and I guess we kind of touched
on it earlier about how the under 15 age category
doesn't have that technical element. So it's
whether, particularly in in -house competitions,
we could bring that technical assessment and
the influence that has on their overall score
back in a little bit more. Obviously, generally,
athletes with better technical competency will
lift more, but it doesn't always work like that.
And you may see the athletes that have poor technical
competency, but because they have kind of better
strength or power, they can get away with it
a little bit more. So maybe adding in some technical
scoring as well might complement that. Measuring
maturity, adjusting competition. So they are
a little bit fair through keeping this technical
element up to 15 years of age, where these differences
are biasing the outcome, potentially, as they
did in the study. And using this information
to program and to guide and develop athletes
according to their actual biological maturation
stage, not necessary to the date they were born.
Two questions to finish. The first one is, what
is your favorite... I'm going to go really controversial
as a, in theory, weightlifter, but at the moment
it's got to be a split squat. What? What? Sorry.
I just think, well, I... hurt my ankle I spray
my ankle before Christmas and squatting just
it's not enjoyable at the moment doesn't look
as good and you can't beat a split squat just
to keep that strength development up and not
compromise on my form with my bad ankle got it
got it I respect that all right where people
can find you if they want to follow your research
ask a question or just see what you're up to
where should they go I'm rubbish on social media
and I apologize now I'm always really good on
email. I'm one of those losers. So any questions,
by all means, I welcome an email. But I do have
social media, so I can be found on Twitter. I'm
also pretty good on ResearchGate as well. If
anybody wants any of the research kind of sharing
or whatnot, probably best to drop a message in
my inbox on ResearchGate. X is at StephMorris979.
But yeah, maybe if people message me on there,
I might become a little bit better. Excellent.
Incentive. All right, Sveta. Thank you so, so
much. Pleasure to meet you again and all the
best. Yeah. Thank you, Alex.